Adhesive compositions, particularly conductive adhesives, have recently gained great popularity in the microelectronics industry. These adhesives are used for a variety of purposes with one of the more prominent uses being the attachment of a semiconductor die, dies or chips, to a substrate, or other support medium. One common problem associated with these adhesives is that upon exposure to high temperatures they exhibit a tendency to undergo outgassing, wherein absorbed or occluded gases, formed during the curing of the adhesive, or during subsequent heat aging of the cured adhesive due to thermal instability, are released. This is a critical problem since, all too often, the success or failure of an electrical component is a direct function of the degree of outgassing undergone by the adhesive resulting in void formation within the adhesive, thereby adversely affecting the thermal and electrical properties of the adhesive. Another problem in regard to such adhesives is ionic contamination by alkali metal (e.g., sodium and/or potassium) and chloride species which, under certain circumstances, can lead to corrosion of the electrical leads in the vicinity of the adhesive.
Recently, in U.S. Pat. No. 4,557,860 to A. L. DiSalvo et al. an adhesive system was described which comprised, as essential ingredients, an epoxy resin, a soluble polyimide resin, and a monoepoxy diluent. Such an adhesive is curable by use of conventional epoxy curing agents. If conductive adhesives are desired with such components, a suitable conductive filler can be added to such compositions.